Lecroy DDA-125 (LC684?) Combining 4 Channels

[dave_n_s]

Some education please.

I've just acquired a couple of, in most respects, DDA-125s to use as 4 channel scopes.

The manual says that to select all four ADCs to support one 8 GS/s channel, select 1 or preferably Automatic, noting that I need the PP096 input adapter as well.

One unit displays options for 1, 2, 4 & automatic selection of the correct number of channels in the block on the horizontal set-up menu

The other just displays 2 & 4 in the same block on the set up menu.

Neither had the PP096 adapter fitted.

Is anything (hardware or software mod) required to be able to create a single 8 GS/s channel? Am I missing another selection?

On the one that doesn't do what I expected, combining pairs of channels works as it should.

Thanks!

[dave_n_s]

To add to this, we have a couple of DDA-120's which are to a large degree CRT versions of the DDA-125, covered by the same manual. Both of those behave as expected - they offer 1,2, 4, Auto channel options with nothing connected to the inputs, not even an adapter.

Usual prompt responses from Teledyne Lecroy tech support, but the responder wasn't familiar with this generation of scope.

Does that ping any memories of what might be going on?

Thanks

[shakalnokturn]

From what I remember of my LeCroy's:
In timebase menu the DDA-120 would have settings for 1, 2, 4 channel usage and allow to combine to 1 without external adapter, the 9384 will allow 2, 4 channels usage in the menu but external combiner must be connected between channels 2&3 to allow single channel use.

When combining is enabled the channel reallocation should be shown on LHS of the screen as you go above the default 4 channel maximum sample rate.

[KK6IL]

 The PP096 input adapter is an external device that apparently connects all 4 inputs to a single BNC connector.  There are several listed for sale on Ebay starting at $75